The present invention relates generally to signal processors of pulse doppler radar systems and more specifically to a technique and apparatus for making probability of detection measurements in dynamic clutter and electronic counter measure (ECM) environments.
In a pulse doppler radar system, it is often desirable to assess the relative radar performance to provide a measure of radar effectiveness in the presence of sources of interference such as clutter and ECM.
The task of making such measurements is alleviated, to some degree, by the prior art technique in which a test target is injected, and the probability of detection of that test target is measured over some statistically significant number of samples. This technique, however, has the following disadvantages:
The use of a test target (either RF or digital) has the potential for interacting with normal radar performance, possibly degrading the detection sensitivity of the radar, i.e. a relatively large amplitude test target could result in the loss of detection of real smaller amplitude targets;
The use of a test target burdens the subsequent target processing unnecessarily. This burden can become significant as the effect of a single target detection grows combinatorically in pulse doppler target processing functions such as unambiguious range correlation and deghosting;
Only a small number of test targets can be injected each coherent integration period since the amount of interaction with normal target processing becomes intolerable with more than a few test targets. As a result, the gathering of a statistically significant sample of detection measures requires a large number of integration periods;
When a large number of integration periods are required for a probability of detection measurement in a scanning radar, a large azimuth sector will be scanned before a statistically significant probability of detection measurement can be completed. As a result, the measurement cannot follow rapid variations in clutter or ECM and does not accurately portray performance of the radar in narrow azimuth sectors.
In view of the foregoing discussion it is apparent that there currently exists the need for a method of making the probability of detection measurements that uses a reduced number of integration periods while accurately portraying radar performance in an environment containing rapid variations in clutter or ECM with no interaction with normal target processing. The present invention is directed towards satisfying that need.